面向mMIMO系统的模式分割随机接入方案

为提升海量机器类通信（massive machine-type communication,m MTC）设备的随机接入（random access,RA）性能，提出一种面向大规模多输入多输出（massive multiple-input multiple-output,m MIMO）系统的模式分割随机接入（pattern division random access,PDRA）方案。该方案将导频竞争空间扩展到模式域，通过叠加同一ZC(Zadoff-Chu）根序列的L个不同循环移位序列，设计基于“图样叠加”的模式域导频，在不增加物理资源的前提下扩大导频集合。仿真结果表明，在不影响信道估计和数据检测性能的前提下，与传统RA方案相比，PDRA方案能够显著降低导频碰撞概率，提高接入成功率。

Pattern division random access (PDRA) scheme for mMIMO systems

To enhance the massive machine-type communications (mMTC) random access (RA) performance, a pattern division random access (PDRA) scheme was proposed for massive multiple-input multiple-output (mMIMO) systems.In this scheme, the pilot contention space was expanded to the pattern-domain.To enlarge the size of contention space without resorting to increasing the physical resources, the pattern-domain pilot was constructed based on the superposition of L cyclically-shifted Zadoff-Chu (ZC) sequences.Simulation results illustrate that the PDRA scheme can reduce pilot collision probability significantly, and improve the access success probability compared with the conventional RA scheme, without compromising excessively on channel estimation and data detection performance.